The present invention relates to a mixing machine, and more particularly, to a rotary mixer bowl clamp for a mixing machine.
Commercial and domestic mixers are well known for mixing food stuffs. Such mixers typically include a housing having a support assembly for supporting a drive head over a removable mixing bowl. The mixing bowl is removably coupled to an arcuate bowl support arm, which extends outward from the housing of the mixer, by a pair of rotary mixer bowl clamps. The bowl typically includes a pair of diametrically opposed projections extending radially outward from the bowl which are received on a top surface of the arcuate bowl support arm. The manually rotatable mixer bowl clamps are threadingly received within threaded bores extending through the arcuate support arm, adjacent to the positions where the projections are seated.
The clamps typically include a head component, positioned on the top of the rotary shaft; and the head includes a radially extending jaw portion, a bottom surface of which is adapted to clamp down upon a top surface of one of the radial projections extending from the bowl. The rotary clamps are designed such that rotation of the clamp in one direction simultaneously lowers the jaw and positions the jaw over the radial projection, thus clamping the projection to the arcuate arm. Rotation of the clamp in the opposite direction simultaneously raises the jaw and rotates the jaw away from the projection, thus releasing the projections from the arcuate arm and, in turn, allowing the bowl to be lifted from the bowl support.
The mixing machines typically operate in environments that contain minute airborne solid and fluid particles (i.e., flour, dust, oil, water, etc.). Such particles and fluids often tend to migrate into the mating circumferential surfaces between the cylindrical shafts of the rotatable clamps and the cylindrical bores extending through the arcuate support arm. Thus, over an extended period of time, a substantial amount of such particles and fluids tends to build up within these mating circumferential surfaces, and thus tends to interfere with the rotating operation of the clamps. Significant build-up of such particles and fluids will cause the clamp to "freeze up," thus requiring maintenance to the bowl support and clamp mechanisms.
U.S. Pat. No. 5,029,673 to Harrington describes an attempt to alleviate this problem. Arrington discloses a rotary clamp mechanism that has a rotary shaft with an axial hole extending therethrough. The axial hole includes three radial holes extending from the axial hole to the outer circumferential surface of the shaft, and the axial hole is also in fluid communication with a grease fitting adapted to be mounted to the bottom portion of the shaft. The Harrington clamp allows for the connection of a grease gun to the grease fitting, to provide grease to the axial hole, and subsequently to provide grease through the radial holes and into the mating circumferential surfaces between the cylindrical shafts of the rotatable clamps and the cylindrical bores extending through the arcuate support arm. While this system is effective to promote easier rotary motion of the clamp shaft within the cylindrical shaft, and to vent foreign particulates from entering between the mating circumferential surfaces, the system requires a continuous maintenance schedule, in which a person will have to couple a grease gun to the grease fitting and apply grease to the mechanism at regular intervals. Without such continuous maintenance, the build-up of particles between the mating circumferential surfaces (and even clogging the radial holes) may advance to such a stage that subsequent injections of grease into the mechanism may not correct the problem. Therefore, this system will be disadvantageous in many circumstances, because establishing and maintaining a continuous maintenance schedule for mixer bowl clamps in many commercial outfits and in almost all domestic situations will not occur.
Accordingly a need exists for a mixer bowl clamp mechanism that allows for extended and continuous use without the need to establish and maintain a strict maintenance schedule. A need also exists for a mixer bowl clamp mechanism that prohibits the build up of air borne food particles and fluids between the mating circumferential surfaces between the clamp shaft and cylindrical bore, without the continuous intervention of a maintenance worker.